Method and a stretching device for the holding of a weft thread

ABSTRACT

A method for holding an inserted weft thread in an air jet weaving machine is presented which is provided with a reed ( 8 ). In this method the weft thread is inserted into the air jet weaving machine, is deflected by means of a nozzle ( 3 ) out of the weft insertion direction ( 9 ) and is blown into a receiving opening ( 5   a ) of the catching channel ( 5 ) and held in the same. The position of the nozzle ( 3 ) and of the catching channel ( 5 ) is for this purpose matched to the desired cloth width within the width of the reed. In the named method the nozzle ( 3 ) and the catching channel passage ( 5 ) are arranged at the beat up side of the reed ( 8 ).

This application claims the priority of European Patent Application No. 06120315, filed Sep. 7, 2006, the disclosure of which is incorporated herein by reference.

The invention relates to a method for the holding of an inserted weft thread in accordance with the preamble of claim 1 and to a corresponding stretching device in accordance with the preamble of claim 6 and also to a weaving machine for carrying out such a method or provided with such a stretching device.

In an air jet weaving machine the weft thread drawn off from a thread store is accelerated through main and tandem nozzles and inserted into a shed in which it is transported further with the aid of so-called auxiliary nozzles or relay nozzles. During the weft insertion the weft thread is guided in a weft channel which is formed in the reed. Following the reed there is normally provided a stretching device in order to stretch the end portion of the weft thread at the catching side and to hold it firmly. In the stretching device, which is frequently termed a catching or holding device, the end portion of the weft thread at the catching side is engaged by a nozzle jet and directed into an opening of a catching tube or catching channel and is held there by the air flow of the nozzle jet. The disadvantage of this arrangement of the stretching nozzle is the circumstance that the reed and if required also the cloth table has to be adjusted with a change of the cloth width.

In the document JP 8-113852 A a stretching device is shown in FIGS. 1-4 which is arranged within the width of the reed so that the reed does not have to be adjusted to the cloth width. The stretching device shown includes a nozzle block which is arranged at the beat up side of the reed as well as a catching tube which is arranged at the oppositely disposed side of the reed. By means of a nozzle contained in the nozzle block the end portion of the weft thread catching side is deflected out of the weft insertion direction and directed through an intermediate space formed between the reed teeth of the reed into an opening of the catching tube. The stretching device shown in document JP 8-113852 A has the disadvantage that, with an inadequate formation of the intermediate space between the reed teeth, turbulences can arise at the same so that the reliable reception of the weft thread in the opening of the catching tube is not guaranteed. If, on the other hand, the intermediate space between the reed teeth is made adequately large, then the danger exists that the reed teeth that are affected can be irreparably deformed and cloth faults can arise at this point when the cloth width is enlarged at a later point in time.

The object of the invention is to make available a method and a stretching device for the holding of an inserted weft thread in an air jet weaving machine, which stretching device can be displaceably arranged within the width of the reed, whereby the adjustment of the reed and of the cloth table with changes of the cloth width is avoided. In addition an irreparable deformation of the reed teeth by the stretching device should be avoided as far as possible. A further object of the invention is to make available a weaving machine for carrying out such a method and having such a stretching device.

This object is satisfied in accordance with the invention by the method defined in claim 1 and by the stretching device defined in claim 6 and also by the air jet weaving machine defined in claim 12.

In the method of the invention for the holding of an inserted weft thread in an air jet weaving machine provided with a reed, the weft thread is inserted into the air jet weaving machine, is deflected out of the weft insertion direction by means of a nozzle having a nozzle opening and is blown into a receiving opening of a catching channel and held in the same. The position of the nozzle and of the catching channel is matched within the width of the reed to a desired cloth width, i.e. to the width of the fabric to be manufactured. The method is characterized in that the nozzle opening of the nozzle and the catching channel are arranged at the beat up side of the reed. The weft thread is advantageously deflected by means of the nozzle into a direction transverse to the weft insertion direction, for example into a direction which extends essentially perpendicular to the weft insertion direction.

In an advantageous embodiment the nozzle includes a nozzle tube which is disposed at least partly between two reed teeth of the reed, for example in a region disposed towards the nozzle opening, for example in the region of a lower reed nose.

In a further advantageous embodiment a weft thread introduced into the catching channel is blown by means of a second nozzle out of the receiving opening of the catching channel. This is in particular of advantage when the weft thread is extra long and cannot be completely drawn out of the catching channel after the beat up through the backward movement of the reed. The first nozzle is expediently so timed that the nozzle jet is interrupted after the beat up.

In a further advantageous embodiment the weft thread is returned by means of the catching channel to a weft channel provided in the reed.

The stretching device in accordance with the invention for the holding of an inserted weft thread in an air jet weaving machine provided with a reed includes a catching channel and a nozzle having a nozzle opening, the blowing direction of which differs from the weft insertion direction in order to deflect an end portion of the weft thread by means of the nozzle out of the weft insertion direction and to blow it into the receiving opening of the catching channel. For this purpose the nozzle and the catching channel are expediently designed and can be installed such that an end portion of the weft thread can be deflected by means of the nozzle out of the weft insertion direction and can be blown into a receiving opening of the catching channel. Furthermore, the stretching device includes at least one fastener part in order to secure the catching channel and the nozzle and in order to arrange the stretching device displaceably within the width of the reed. For this purpose the at least one fastening part is expediently designed such that the stretching device is displaceable and can be installed within the width of the reed. The stretching device is characterized in that the catching channel and the nozzle opening of the nozzle can be installed at the beat up side of the reed by means of the at least one fastening part. For this purpose the at least one fastening part is expediently designed such that the catching channel and the nozzle opening can be installed by means of the same at the beat up side of the reed. The blowing direction of the nozzle is advantageously directed transverse to the weft insertion direction, for example essentially perpendicular to the weft insertion direction.

In an advantageous embodiment a nozzle includes a nozzle tube which has an oval or shallow cross-section in at least one region, for example towards the nozzle opening, in order to arrange the nozzle tube between two reed teeth of the reed, for example in the region of a lower or upper reed nose, and in order to avoid damage to the reed as far as possible.

In a further advantageous embodiment the stretching device includes a second nozzle in order to blow a weft thread introduced into the catching channel out of the receiving opening of the catching channel. For this purpose the second nozzle is expediently designed and arranged such that by means of the same a weft thread introduced in the catching channel can be blown out of the receiving opening of the catching channel. The second nozzle is advantageously arranged at the catching channel and/or at a fastening part for the same.

In a further advantageous embodiment the catching channel has at least one bend in order to return the weft thread to a weft channel provided in the reed. For this purpose, the catching channel is expediently bent and can be installed in such a way that the outlet of the catching channel aims into the weft channel in the state ready for operation.

The invention additionally includes an arrangement containing a reed and a stretching device in accordance with one of the above described embodiments.

Furthermore, the invention includes an air jet weaving machine equipped for carrying out a method in accordance with the above description or with a stretching device in accordance with one of the above described embodiments or with an arrangement in accordance with the above description.

The method of the invention and the stretching device of the invention for the holding of an inserted weft thread in an air jet weaving machine have the advantage that, with a change and in particular a reduction of the cloth width, it is possible to dispense with the adjustment of the reed and of the cloth table because the stretching device of the nozzle and the catching channel are displaceably arranged within the width of the reed. Furthermore, an irreparable deformation of the reed teeth can be largely avoided by a flattened design of the nozzle tube. In addition it is advantageous that the deformation of the reed teeth is, to a considerable degree, a part of an elastic nature thanks to the arrangement of the nozzle tube in the region of the lower reed nose. The above-described method and the above described stretching device are suitable for all current reed heights if the fastening parts are for example formed in accordance with the specific embodiment. Moreover, using the described method and the described stretching device both flat weft yarns and also standard weft yarns can be reliably held.

The above description of the embodiments serves merely as an example. Further advantageous embodiments can be seen from the dependent claims and the drawing. Moreover, in the context of the present invention, individual features from the described embodiments or illustrated embodiments and from the described or illustrated variants can be combined with one another in order to form new embodiments.

In the following the invention will be explained in more detail with reference to the specific embodiment and with reference to the drawing. There are shown:

FIG. 1 a view of an embodiment of a stretching device in accordance with the present invention and

FIG. 2 a side view of the same embodiment.

The embodiment of a stretching device shown in FIGS. 1 and 2 in accordance with the present invention serves for the holding of an inserted weft thread in an air jet weaving machine which is provided with a reed 8. The reed 8 includes a plurality of reed teeth 8 a and can for example, as shown in FIG. 1 be arranged on a sley 7. The stretching device in accordance with the invention includes a catching part 1.2 having a catching channel 5 and a nozzle part 1.1 having a nozzle 3 which has a nozzle opening, with the blowing direction of the nozzle deviating from a weft insertion direction 9. By means of the nozzle 3 the end portion of the weft thread at the catching side can be deflected out of the weft insertion direction 9 and blown into a receiving opening 5 a of the catching channel 5. The receiving opening 5 a can for example, as shown in FIG. 2, be arranged alongside an upper reed nose.

Furthermore, the stretching device 1 includes at least one fastening part in order to fasten the catching channel 5 and the nozzle 3 and in order to displaceably arrange the stretching device within the width of the reed 8. For the attachment a plurality of the fastening parts 2 a, 2 b, 2 c can, for example, be provided as shown in FIGS. 1 and 2 and the nozzle 3 can for example be displaceably arranged on the reed 2 by means of its own fastening part 2 c. For this purpose a groove extending along the sley can for example be used, such as is used for the fastening of the relay nozzles. The catching channel 5 can, for example, as shown in FIGS. 1 and 2, be displaceably arranged at the upper part of the reed 8 by means of one or more fastening parts 2 b, 2 c. Furthermore, the catching channel 5 can also be displaceably secured to the sley 7, for example by means of a groove extending along the sley.

The catching channel 5 and the nozzle opening and/or the nozzle can be installed at the beat up side of the reed 8 by means of the fastening part or fastening parts so that the weft thread can be directly deflected by means of the nozzle 3 into the receiving opening 5 a of the catching channel 5, for example in that the blowing direction of the nozzle 3 is directed into the receiving opening 5 a of the catching channel. In an advantageous variant the catching channel 5 extends upwardly or downwardly in a first section, i.e. essentially parallel to or at an acute angle to the direction of the reed teeth, for example at an acute angle of not more than 45°. In a further advantageous variant the blowing direction of the nozzle 3 is directed transverse to the weft insertion direction 9, for example as shown in FIG. 1 essentially at right angles to the weft insertion direction.

In an advantageous embodiment the nozzle 3 includes a nozzle tube 3 a which has an oval or flattened cross-section at least in a region 3′a, for example towards the nozzle opening, in order to arrange the nozzle tube between two reed teeth of the reed 8, for example in the region of a lower reed nose 8 c. In an advantageous variant the nozzle opening is flush or almost flush with an outline of the reed nose 8 c in order to avoid contact of the nozzle tube by the cloth table, with the deviation advantageously amounting to less than +/−2 mm or less than +/−5 mm. In a further advantageous variant the nozzle part 1.1 includes a blowing medium feed 3′.

In a further advantageous embodiment the stretching device 1 includes a second nozzle 4 in order to blow a weft thread introduced into the catching channel 5 out of the receiving opening 5 a of the catching channel. The second nozzle 4 can, for example, as shown in FIG. 1, be provided at the catching part 1.2, with the nozzle opening advantageously being disposed in the vicinity of the receiving opening 5 a. The second nozzle 4 can however also be separately arranged, for example between two reed teeth of the reed 8.

In a further advantageous embodiment the catching channel 5 has at least one bend in order to return the weft thread, as shown in FIG. 1, to a weft channel 8 b provided within the reed 8. Through the deflection of the weft thread at the receiving opening 5 a, which is advantageously provided with an edge, and through the above-mentioned bending of the catching channel 5, the weft thread is deflected twice and the holding force is enhanced.

An embodiment of the method of the invention for holding an inserted weft thread in an air jet weaving machine which is provided with a reed 8 will be described in the following with reference to the FIGS. 1 and 2. In the method the weft thread is inserted into the air jet weaving machine, is deflected by means of a nozzle 3 having a nozzle opening out of the weft insertion direction 9 and is blown into a receiving opening 5 a of the catching channel 5 and held in the latter. The position of the nozzle 3 and of the catching channel 5 is matched for this purpose within the width of the reed 8 to the width of the cloth to be manufactured. The method is characterized in that the nozzle opening of the nozzle 3 and the catching channel 5 are arranged at the beat up side of the reed 8. The nozzle opening and the catching channel 5 are advantageously so arranged that the weft thread is blown by means of the nozzle directly in to the catching channel.

In an advantageous embodiment the weft thread is deflected by means of the nozzle 3 into a direction transverse to the weft insertion direction 9, for example into a direction which extends substantially perpendicular to the weft insertion direction. An edge is advantageously formed at the receiving opening 5 a so that the friction which arises as a result of the deflection of the weft thread at the receiving opening 5 a is enhanced.

In an advantageous embodiment the nozzle 3 includes a nozzle tube 3 a which is disposed at least partly, for example in a region 3′a disposed towards the nozzle opening, between two reed teeth of the reed 8, for example in the region of a lower reed nose 8 c. The cross-section of the nozzle 3 a is advantageously made oval or flattened in this region.

In a further advantageous embodiment a weft thread inserted into the catching channel 5 is blown by means of a second nozzle 4 out of the receiving opening 5 a of the catching channel. This is in particular of advantage when the weft thread is extra long and is not drawn fully out of the catching channel after the beat up by the return movement of the reed. In an advantageous variant the two nozzles 3 and 4 are individually timed and each supplied with blowing medium by means of a respective valve, for example with air. The second nozzle 4 is advantageously supplied with the blowing medium during the blowing out whereas the first nozzle 3 is for example so timed that the nozzle jet is interrupted after the beat up.

In a further advantageous embodiment the weft thread is returned by means of the catching channel 5 to a weft channel 8 a provided in the reed 8, for example in that the catching channel is so bent and so arranged that the outlet of the catching channel opens into the weft channel.

The method in accordance with the invention and the stretching nozzle in accordance with the invention for the holding of an inserted weft thread in an air jet weaving machine have the advantage that the reed and the cloth table do not have to be adapted on reductions of the cloth width. Furthermore, a possible deformation of the reed teeth can be kept small thanks to the flattened design of the nozzle tube. 

1. A method for holding an inserted weft thread in an air jet weaving machine provided with a reed (8) in which method the weft thread is inserted into the air jet weaving machine, the weft thread is deflected by means of a nozzle (3) having a nozzle opening out of the weft insertion direction (9) and into a receiving opening (5 a) of a catching channel (5), the weft thread is held in the catching channel (5) and the position of the nozzle (3) and of the catching channel (5) is matched within the width of the reed (8) to the desired cloth width, characterized in that the nozzle opening of the nozzle (3) and the catching channel (5) are arranged at the beat up side of the reed (8).
 2. A method in accordance with claim 1, wherein the weft thread is deflected by means of the nozzle (3) in a direction transverse to the weft insertion direction (9).
 3. A method in accordance with, claim 1, wherein the nozzle (3) includes a nozzle tube (3 a) which is arranged at least partly between two reed teeth of the reed (8), in particular in the region of a lower reed nose (8 c).
 4. A method in accordance with, claim 1, wherein a weft thread introduced into the catching channel (5) is blown by means of a second nozzle (4) out of the receiving opening (5 a) of the catching channel (5).
 5. A method in accordance with, claim 1, wherein the weft thread is returned by means of the catching channel (5) into a weft channel (8 b) provided in the reed (8).
 6. A stretching device for holding an inserted weft thread in an air jet weaving machine provided with a reed (8), which stretching device (1) includes a catching channel (5) and a nozzle (3) having a nozzle opening, the blowing direction of which differs from a weft insertion direction (9) in order to deflect an end portion of the weft thread by means of the nozzle (3) out of the weft insertion direction (9) and into a receiving opening (5 a) of the catching channel (5) and at least one fastening part (2 a, 2 b, 2 c) in order to secure the catching channel (5) and the nozzle (3) and to displaceably arrange the stretching device (1) within the width of the reed (8), characterized in that the catching channel (5) and the nozzle opening of the nozzle (3) can be installed by means of the at least one fastening part (2 a, 2 b, 2 c) at the beat up side of the reed (8).
 7. A stretching device in accordance with claim 6, wherein the blowing direction of the nozzle (3) is aligned transverse to the weft insertion direction (9).
 8. A stretching device in accordance with, claim 6, wherein the nozzle (3) includes a nozzle tube (3 a) which has an oval or flat cross-section at least in one region (3′a) in order to arrange the nozzle tube (3 a) between two reed teeth of the reed (8), in particular in the region of a lower reed nose (8 c).
 9. A stretching device in accordance with, claim 6, including a second nozzle (4) in order to blow a weft thread inserted into the catching channel (5) out of the receiving opening (5 a) of the catching channel.
 10. A stretching device in accordance with, claim 6, wherein the second nozzle (4) is arranged at the catching channel (5) and/or at a fastener part (2 a, 2 b) of the same.
 11. A stretching device in accordance with, claim 6, wherein the catching channel (5) includes at least one bend in order to return the weft thread to a weft channel (8 c) provided in the reed (8). 